Methods and apparatus for making granules

ABSTRACT

THIS INVENTION RELATES TO A METHOD OF MAKING GRANULES FROM BOTH RELATIVELY BRITTLE AND SOFT MATERIALS, SUCH AS FROZEN PVC OR RUBBER, AND TO AN APPARATUS FOR PERFORMING THE METHOD. CHARACTERISTIC OF THE METHOD IS THAT THE GRANULES ARE CUT INDIVIDUALLY ONE AFTER THE OTHER FROM EDGE OF A CONTINUOUSLY SUPPLIED WEB TOWARDS THE MIDDLE OF SAID WEB OR TOWARDS THE MIDDLE OF A NUMBER OF WIDTH SECTIONS OF SAID WEB BY CUTTING   MEANS EACH HAVING TWO CUTTING EDGES WHICH MAKE AN ANGLE WITH EACH OTHER AND WITH THE PLANE OF THE WEB.

United States Patent Inventor Carl Vicktor Astrand Hanaskog, Sweden Appl, No. 712,799

Filed Mar. 13,1968

Patented June 28, 1971 Priority Mar. 13, 1968 Sweden 3423/1967 Assignee Tarkett A B, Malmo C. Sweden METHODS AND APPARATUS FOR MAKING GRANULES 16 Claims, 7 Drawing Figs.

83/49, 83/355, 83/660, 83/673, 83/906 Int. Cl B26d 5/20 Field of Search 83/355,

Primary Examiner-James M. Meister Atlomey- Beveridge & De Grardi ABSTRACT: The invention relates to a method of making granules from both relatively brittle and soft materials, such as frozen PVC or rubber, and to an apparatus for performing the method. Characteristic of the method is that the granules are I cut individually one after the other from the edge of a continuously supplied web towards the middle of said web or towards the middle of a number of width sections of said web by cutting means each having two cutting edges which make an angle with each other and with the plane of the web.

PATENTED JUH28 lBil SHEET 1 BF 4 lNVi-NTOR; CARL VICKTOR ASTRA PATENTEU JUH28 1W1 SHEET 3 0F 4 INVENTOR: CARL VlCKTOR ASTR-A D METHODS AND APPARATUS FOR MAKING GRANULES This invention relates to a method of making granules from a material in the form of a web of synthetic plastic, rubber or like material.

In making granules from weblike material one at present employs a two-step method in which the web is first cut into longitudinal strips some millimeters wide and then these strips are supplied to a rotor equipped with radially projecting cutting edges for transversely comminuting the strips. A great many disadvantages are encountered in such manufacture of granules preferably with respect to the cutting means acting longitudinally of the web, which have to operate with extremely high precision to produce uniform granules. It is expensive to manufacture and mount these cutting means and besides they are often subjected to disturbances, which results in unsatisfactory granules, among other things the occurrence of so-called needles, i.e. long and narrow pieces of the starting material mixed with the granules. When the number of such needles becomes too large the apparatus has to be stopped for adjustment and possible exchange of cutting means. Moreover, the cutting means are rapidly worn and therefore have to be replaced at frequent intervals, which is also the case with the transversely acting cutting means. As a summary, the present granulating apparatus are expensive to manufacture and to maintain and often cause operational disturbances and produce granules which may contain pieces of unacceptable shape. Besides, these apparatus have a high power consumption and can handle synthetic plastics webs of but narrow width of not more than 50 cm.

The present invention has for its object to produce granules in an altogether novel manner in which the arrangement of cutting means operating longitudinally of the web can be dispensed with and granules of a considerably more uniform shape can be made from webs of any desired width to attain this, the granules are cut individually in single operation from the edge of the web which is of a width-considerably exceeding the largest dimension of the granules.

The granules are suitably cut in sequence from one and the other longitudinal edge of the web towards the middle thereof, or from one and the other end of the web towards the middle of a number of width sections of the web. It will be realized that only a few cutting means are in engagement with the web at the same time, for which reason the power consumption can be reduced considerably. Each granule is suitably cut along two cutting lines that make an angle with one another and cutting preferably takes place along the said two cutting lines approximately simultaneously, beginning at the point of inter section of said cutting lines. The other cutting lines are already free due to granules having been cut earlier, or are formed by the longitudinal and transverse edges of the web when granulation is started at the end of a web.

In the granulation of particularly soft elastic materials, such as rubber and the like, it has also proved extremely advantageous for cutting the granules first to make a longitudinal cut from the free edge of the web and immediately after that to effect a transverse cut preferably from the end of the longitudinal cut.

The invention is also concerned with an apparatus for manufacturing granules in accordance with the method described, said apparatus comprising a cutting device and means for supplying the material to the cutting device. This apparatus is characterized in that the cutting device is in the form of a rotary cylinder in the circumferential surface of which there are placed cutting means each of which is arranged to individually cut granules in one operation from the edge of the web of material supplied approximately radially to the cylinder at a speed suited to the rate of rotation of the cylinder, the cutting being performed against an abutment extending in parallel with the axis of said rotary cylinder and situated close to the circumferential surface thereof.

This apparatus can be built at a cost which is but a fraction of the cost of a conventional apparatus and will be of reliable operation for long periods and require but little power compared to prior-art apparatus.

These features of the invention and the advantages gained thereby will appear from the following specification in which reference is made to the accompanying drawings.

In the drawings:

FIG. I shows a side elevation and cross section of the apparatus according to the invention;

FIG. 2 shows a front view, partly in section of the apparatus in FIG. I;

FIG. 3 is a front elevation of one form of cutting means of this invention as employed in FIG. 2 (left end);

FIG. 4 is a side view ofthe cutting means of FIG. 3;

FIG. 5 is atop view of the cutting means of FIG. 3;

FIG. 6 shows a cutting diagram;

FIG. 7 is an enlarged view of the cylinder of FIG. 2 bearing cutting means arranged in a plurality of pairs of helices in one width section and in plural width sections each having cutting means arranged in a pair of helices.

The apparatus shown in FIGS. 1 and 2 comprises a frame 10 and a flat horizontal feed table 11 disposed thereon. A web of synthetic plastics I2 is laterally guided by supports 36 as it is moved over the table 11 with the aid of drive rollers 13, 14. The web is moved up to a cylindrical cutting device to be described in the following. The feed table 11 and the cutting device 15 are adjustable relative to each other in the tangential direction of the cutting device by means (not shown). Mounted at the end of the feed table II facing the cutting device is an abutment 16 which extends throughout the width of the cutting device. The abutment 116 is upwardly inclined and can be fixed in any desired position by means of a fastening 17 and screws 18. For its operation the cutting device 15 has connected thereto a drive motor 19 by means of a V-belt arrangement 20. Of the drive rollers 13, 14, roller 13 is driven by means of a V-belt 23 from a motor 21 via a speed governor 22 for regulating the feed rate of the web 12 towards the cutting device 15, while the roller 14 is idling. The distance between the drive rollers is adjustable in a known manner. For regulating the tension of the drive belts the motor 15 is mounted for pivotment at 24 and can be fixed in the adjusted position by screw means 25, while the motor is shiftable on its support with the aid of screw means 26 and can be clamped thereto by means of screws 27 extending through elongated openings in the baseplate of the motor. Mounted above the cutting device I5 is a protective casing 28 which can be swung aside. A chute 29 leads out of the housing from the space beneath the cutting device.

The cutting device 15 comprises juxtaposed circular discs 31 mounted on a shaft 30. In a manner that will appear from FIG. 4, cutting means 32 preferably of hard metal are attached to each of said discs, said cutting means being as broad as the disc so that when projected onto a generatrix the cutting means will directly connect on to each other. The heads of the cutting means may of course also be so shaped as to slightly overlap when so projected. The discs 31 are kept together on the shaft 39 by means of nuts 33 passed onto the threaded ends of the shaft 30 and screwed towards one another. Each cutting means 32 comprises a stem 34 which is secured in a suitable manner in a corresponding recess in the disc 31, and a head 35 having two cutting edges A and B which in horizontal projection make a right angle with one another and in vertical projection are upwardly inclined from the right-hand front corner, as viewed in FIG. 3. It will be seen from FIGS. 3-5 that when such a cutting means is moved vertically downward against a plastics web two cutting lines will be provided, starting from the point of intersection of the cutting lines. If the other two cutting lines are free already, which is the case if for instance the pieces designated I in FIG. 6 are cut out, a granule is obtained. The shown and described arrangement of the discs 31 of the cutting means 32 only serves to illustrate an advantageous embodiment which enables simple adjustment of the cutting means in relation to each other, as will be described more in detail in the following. Instead of discs other devices of course are conceivable for securing the cutting means, and the latter need not necessarily be shaped in the manner shown; upon granulation of rubber, for instance,

cutting means having two cutting edges one of which extends in the direction of feed of the web 12 while the other extends transversely of said direction, have proved extremely advantageous. The main thing is that granules are cut in one operation.

The cutting means are substantially arranged in the manner shown in FIG. 2, i.e. in two oppositely directed helices which start each from one end of the cylinder formed by the discs 31 and which meet at the middle of the cylinder. Depending upon the circumference of the cylinder the cutting means 32 are mounted along one, two or more pairs of such pairs of helices. A second pair of cutting elements arranged in oppositely oriented helices is shown in dotted line representing a like arrangement on the reverse side of cutting device 15, elements corresponding to 32, 34 and 35 being there represented at 32', 34 and 35'. Each pair comprises like elements of one helix and oppositely oriented elements of the other helix, in respect to the opposite direction of cutting at edge B. In FIG. 2 one pair of helices extend throughout the width of the cylinder but it is a matter of course that the cylinder, if it is of very large width, will have to be divided into several width sections each having one pair of helices. A portion of a pair of helices extending leftward from the set shown in FIG. 2 is also illustrated in FIG. 7, wherein elements 32", 34" and 35" correspond to elements 32, 34 and 35. Positioning of the cutting means is realized by relative rotation of the discs 31 before the discs are clamped with the aid of the nuts 33. If the cutting device designed in the manner shown in FIG. 2 is rotated and a web of plastic is moved up to the periphery of the cutting device, granules will be cut out in the manner illustrated in exaggerated size of granules in FIG. 6, i.e., there are first cut two granules as at 1, located at the longitudinal edge or leading end of the web and close to the transverse edges, and then adjoining granules 2, etc., until granules 8 have been severed, whereupon another pair of helices formed by the cutting means will become effective due to the rotation of the cutting device so that l, 2, etc. are then cut. Since cutting laterally of the web proceeds symmetrically from both sides toward the middle of the web the web will not be laterally displaced. Equivalently, the helices may be reversed so that the cutting proceeds symmetrically from the center position outwardly to the edges. A single helix of cutter elements extending adjacently entirely across the web could beemployed but with the disadvantage that lateral displacement might occur.

It will be readily understood by those skilled in the art that the invention is not restricted to the embodiment described in the foregoing and illustrated in the accompanying drawings but can be modified within the scope ofthe appended claims.

Iclaim:

1. An apparatus for making granules comprising a frame, a feed table on said frame, a cutting device in the form of a cylinder which is mounted at the end of the feed table, means for conveying a web of material along the feed table towards the cutting pointed device, cutting means mounted in the circumferential surface of the cutting device and disposed along at least two pairs of oppositely oriented helices, the helices in each pair starting from axially opposed points at the ends of a number of width sections of the circumferential surface of the cutting device and meeting in the middle of the width sections, and means for driving the cutting device and the means for conveying the web of material along the feed table towards the cutting device, said cutting means in each pair of helices when projected onto a generatrix being located adjacent to one another to cut in sequence juxtaposed portions of the web of material in the transverse direction thereof, each cutting means having two cutting edges which make an angle with one another and have an angle of inclination to the plane of the web of material that corresponds to the direction and the cutting sequence along the two cutting lines.

2. Apparatus for making granules, comprising a driven rotary cylinder, means for continuously supplying a web of material radially toward the periphery of said cylinder, said cylinder including individual granule point penetration and lateral cutting means mounted at the circumferential surface thereof along a pair of oppositely oriented helices commencing at the sides of the circumferential surface of the cylinder and meeting at the middle thereof for cutting a lateral row of granules during a rotation of the cylinder.

3. Apparatus as claimed in claim 2, said cutting means being mounted at the circumferential surface of the cylinder along a plurality of pairs of oppositely oriented helices, the helices of each pair starting from points at the sides of a number of width sections of the circumferential surface of the cylinder and meeting in the middle of the respective width sections.

4. A method of making like granules from a material in the form of a web, comprising cutting in discrete steps successive rows of granules from web portions respectively adjacent laterally across a web portion by cutting two adjacent sides of a four-sided granule from a web previously out along two remaining adjacent sides of the granules, said adjacent side cuts thereby severing the granules individually from the web, said cutting steps in each row being made in a continuing series while the web is being advanced longitudinally at a rate to offset longitudinally portions cut in successive rows sufficiently to space repeating cuts at each lateral position according to one desired granule dimension.

5. A method in claim 3, wherein each successive cutting step comprises cutting a line laterally and an intersecting line longitudinally of the web each commencing at a point of intersection therebetween.

6. A method as in claim 4, wherein said cutting steps in each row comprise two contemporaneous sequences of steps each beginning from a lateral edge of a web portion and proceedings toward the center thereof in successively adjacent longitudinally offset steps.

7. A method according to claim 4, wherein each said step comprises piercing the web at an interior point and then cutting out lines along two sides of a granule substantially simultaneously each extending to a free edge of the web.

8. In a granule cutting device for cutting granules progressively along lateral rows of granule-forming portions of a web and successively by rows as the web is advanced toward said device,

an array of cutters arranged for rotation along a cylindrical locus; including a plurality of disc elements mounted concentrically on a driving shaft in adjustable relative rotary orientation; means securing said elements in a selected relative orientation;

mounting means for a cutter element in a plurality of said disc elements comprising slot means extending inwardly from the periphery thereof for receiving a cutter element supporting bar; and

a cutter element comprising a perforating point and two cutting edges supported by a bar secured by said slot means.

9. A method according to claim 4 including continuously advancing the web during said cutting steps for the granules of each row and for a sequence of rows the first granule of each row commencing as the final granule of a preceding row is cut.

10. The method of making dimensioned granules from a web of material which is wide relative to the desired granule dimensions, comprising the steps of advancing said web beyond a supporting surface therefor to form an unsupported edge portion substantially broader than a granule dimension, perforating said web portion at points taken in successive order across the width thereof,

progressively cutting along two separate lines intersecting at said point from each perforation to two adjacent web edges to thereby form two cut edges of each granule, said lines being predominantly longitudinal and lateral, respectively, of the advancing web. 11. In the method of claim 10 said points of perforation being arranged diagonally across the web.

12. In the method of claim 10 said progressive cutting of each lateral line being substantially completed during an interval between making of adjacently lateral perforations.

13. Apparatus for making dimensioned granules from a web of material which is wide relative to the desired granule dimensions, comprising:

means for advancing said web beyond a supporting surface therefor to form an unsupported edge portion broader than a granule dimension;

means for perforating said web portion at points taken in successive order across the width thereof;

means for cutting progressively along two lines intersecting at said point from each said perforation to two adjacent web edges to thereby form two cut edges for each granule cut, said lines being predominantly longitudinal and lateral, respectively of the web.

14. Apparatus according to claim 13, said means for perforating comprising a series of pointed tools carried in at least one helical pattern about a rotative cylinder in the path of the web movement.

15. Apparatus for making granules, comprising a rotary driven cylinder, means for continuously supplying a web of material radially toward the periphery of said cylinder, said cylinder including individual granule cutting means mounted at the circumferential surface thereof along a pair of oppositely oriented helices commencing at the sides of the circumferential surface of the cylinder and meeting at the middle thereof for cutting a lateral row of granules during a rotation of the cylinder, each said cutting means mounted in said cylinder having two cutting edges which make an angle with one another and have an angle of inclination to the plane of the web of material that corresponds to the direction and the cutting sequence along the two cutting iines.

16. A method of making dimensioned granules from a material in the form of a web, comprising impact cutting of granules without a shearing edge in ordered succession from a web which is of a width considerably exceeding the largest dimension of the granules in repeated row sequences of cutting operations during continued web advancement, each sequence progressing laterally of the web while advancing the web longitudinally by one granule dimension during a sequence of cutting operations, the successive granules of a row being cut along two intersecting longitudinal and lateral lines intersecting and lateral lines intersecting like lateral and longitudinal lines of cut forming preceding granules, said cutting along two intersecting lines taking place substantially simultaneously commencing at the point of intersection of the two lines.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventor(s) ASTRAND, CARL VICKTOR It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cover Page.

"Priority date, March 13, 1967."

Signed and sealed this 9th day of November 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting, Commissioner of Patents FORM PC4 (1 uscoMM-Dc 60376-P69 U.S, GOVERNMENY HUNTING OFFICE 19! O-Jfifi'334 

